public class Pillar {
	Geometry bottom;
	double height;
	Pillar (Geometry bottom,double height) {
		this.bottom=bottom; this .height = height;
	}
	public double getVolume(){
		if(bottom==null){
			System.out.println("没有底，无法计算");
			return -1;
		}
		return bottom.getArea()*height;
	}
}
